Answer: A. Transverse
Explanation:
Sound is a mechanical transverse wave, it travels faster in solids than in liquids or gases. This is because the speed of the mechanical waves is determined by a relationship between the elastic properties of the medium in which they are propagated and the mass per unit volume of the medium.
In addition, the speed of sound varies with changes in the temperature of the medium. This is because an increase in temperature means that the frequency of interactions between the particles that transport the vibration increases, hence this increase in activity increases the speed.
Hence:
<h3>Sounds travels in a <u>transverse</u> wave</h3>
Answer:
a. 
b. 
Explanation:
Given:



The runner force average to find given the equations
a.




b.
Work done by the system by this force so





Answer:
a) W = 6.75 J and b) v = 3.87 m / s
Explanation:
a) In the problem the force is nonlinear and they ask us for work, so we must use it's definition
W = ∫ F. dx
Bold indicates vectors. In a spring the force is applied in the direction of movement, whereby the scalar product is reduced to the ordinary product
W = ∫ F dx
We replace and integrate
W = ∫ (-60 x - 18 x²) dx
W = -60 x²/2 -18 x³/3
Let's evaluate between the integration limits, lower W = 0 for x = -0.50 m, to the upper limit W = W for x = 0 m
W = -30 [0- (-0.50) 2] -6 [0 - (- 0.50) 3]
W = 7.5 - 0.75
W = 6.75 J
b) Work is equal to the variation of kinetic energy
W = ΔK
W = ΔK = ½ m v² -0
v =√ 2W/m
v = √(2 6.75/ 0.90)
v = 3.87 m / s
I believe it is because of weight if Timmy is larger and bigger than Maria that would mean he would stop slower just because of his bodyweight pushing on the back of the skateboard while Maria is all those skinny and she doesn’t have as much weight as she can go farther